Words that have identical vowel-based rhyme sounds in the tonic syllable. Moreover, that tonic syllable must start with a different consonantal sound.
There are no pure rhymes for "pack a punch".
Words that have a pure rhyme on their last syllable only.
brunch
    bunch
      crunch
        hunch
          lunch
            munch
              punch
                scrunch
                  Bunche
                    counterpunch
                      Words that "almost" rhyme on the vowel-based rhyme sound of the stressed syllable like: be/eat or maybe/shapely.
                      There are no near rhymes for "pack a punch".
                      Rhymes made up of more than one word. For instance, "jealous" and "tell us" or "shaky" and "make me."
                      There are no mosaic rhymes for "pack a punch".